(1) Field of the Invention
The present invention relates to an automatic path setting apparatus for a synchronous communication system equipped with a network management system, and more particularly, to an automatic path setting apparatus for a synchronous communication system wherein the line configuration settings are performed automatically without the need for the routing by the operator.
(2) Description of the Related Art
In recent years there has been a demand for expansion of broadband ISDNs based on a globally standardized user network interface, and to meet the demand, SDH (Synchronous Digital Hierarchy) has been standardized which is capable of effectively multiplexing various high-speed services as well as existing low-speed services. SDH was standardized by Bellcore/ITU and is called SONET (Synchronous Optical Network) in the United States.
In a conventional transmission network based on PDH (Presiochroncous Digital Hierarchy), where the line configuration need be modified, the wiring of jumpers is physically changed. This method, however, requires much labor and time and lacks flexibility. In SONET/SDH, on the other hand, since each station has a built-in cross-connection function, the setting of the line configuration is performed at each station by means of software setting, and it is unnecessary to change the wiring of jumpers.
Meanwhile, multiplexed frames STM-4, STM-16, etc. used in SONET/SDH have entailed an increase in the line capacity, also increasing the frequency of modifications of the line configuration. Where the line configuration need be modified, if operators are required to visit individual network elements (hereinafter referred to as "NE(s)") which are installed in different places, the efficiency of the setting/modifying operation is low. In view of this, various methods have been put to practical use which include a remote access method wherein the line setting of an NE is modified by means of an overhead control signal transmitted from a remote maintenance terminal, and a method wherein the path setting of an NE is executed by a network management system (hereinafter referred to as "NMS") which performs centralized management of the entire network. The path setting by an NMS will be explained below.
When setting a path by means of an NMS, the operator first specifies NEs which correspond to the start point and end point of the path, respectively, as well as channel numbers of the NEs. The operator also specifies a route and its channel number. In accordance with the specified data, the NMS sets and establishes the path.
In the path setting by means of the conventional NMS, however, it is necessary for the operator to actually check drawings at desk, for example, in order to ascertain the present line configurations, remaining capacities, etc. and determine the route. Also, the operator can only check from the viewpoint of routing to see if the specified two points are connectable through the specified route, and whether or not the connection can really be achieved through the specified channel number remains unknown until the cross-connection setting is actually made with respect to the NEs.